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In Melting Points We Trust: A Review on the Misguiding Characterization of Multicomponent Reactions Adducts and Intermediates. Molecules 2022; 27:molecules27217552. [DOI: 10.3390/molecules27217552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/25/2022] [Accepted: 11/02/2022] [Indexed: 11/06/2022] Open
Abstract
We discuss herein the problems associated with using melting points to characterize multicomponent reactions’ (MCRs) products and intermediates. Although surprising, it is not rare to find articles in which these MCRs final adducts (or their intermediates) are characterized solely by comparing melting points with those available from other reports. A brief survey among specialized articles highlights serious and obvious problems with this practice since, for instance, cases are found in which as many as 25 quite contrasting melting points have been attributed to the very same MCR adduct. Indeed, it seems logical to assume that the inherent non-confirmatory nature of melting points could be vastly misleading as a protocol for structural confirmation, but still many publications (also in the Q1 and Q2 quartiles) insist on using it. This procedure contradicts best practices in organic synthesis, and articles fraught with limitations and misleading conclusions have been published in the MCRs field. The drawbacks inherent to this practice are indeed serious and have misguided MCRs advances. We therefore suggest some precautions aimed at avoiding future confusions.
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Momahed Heravi M, Zadsirjan V, Mollaiye M, Heydari M, Taheri Kal Koshvandi A. Salicylaldehydes as privileged synthons in multicomponent reactions. RUSSIAN CHEMICAL REVIEWS 2018. [DOI: 10.1070/rcr4780] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Novel synthesis of dihydropyrimidines for α-glucosidase inhibition to treat type 2 diabetes: In vitro biological evaluation and in silico docking. Bioorg Chem 2014; 54:96-104. [DOI: 10.1016/j.bioorg.2014.05.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 04/23/2014] [Accepted: 05/05/2014] [Indexed: 11/21/2022]
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Shi DQ, Shi JW, Yao H. Three-Component One-Pot Synthesis of Indeno[2′,1′:5,6]Pyrido[2,3-d]Pyrazole Derivatives in Aqueous Media. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.200900075] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Multi-component One-Pot Synthesis of 4-Aryl Substituted Dihydropyrimidinones and Mechanistic Study Under Solvent-Free Conditions Using NiO2 as Heterogeneous Recyclable Green Catalyst. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES INDIA SECTION A-PHYSICAL SCIENCES 2013. [DOI: 10.1007/s40010-013-0075-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Sahu PK, Sahu PK, Agarwal DD. Efficient and facile synthesis of heterocycles and their mechanistic consideration using kaolin. RSC Adv 2013. [DOI: 10.1039/c3ra40993g] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Karami B, Haghighijou Z, Farahi M, Khodabakhshi S. One-Pot Synthesis of Dihydropyrimidine-Thione Derivatives Using Tungstate Sulfuric Acid (TSA) as a Recyclable Catalyst. PHOSPHORUS SULFUR 2012. [DOI: 10.1080/10426507.2011.616562] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Lal J, Sharma M, Gupta S, Parashar P, Sahu P, Agarwal D. Hydrotalcite: A novel and reusable solid catalyst for one-pot synthesis of 3,4-dihydropyrimidinones and mechanistic study under solvent free conditions. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/j.molcata.2011.09.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Biginelli Condensation: Synthesis and Structure Diversification of 3,4-Dihydropyrimidin-2(1H)-one Derivatives. ADVANCES IN HETEROCYCLIC CHEMISTRY 2012. [DOI: 10.1016/b978-0-12-396530-1.00003-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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A chemical placebo: NaCl as an effective, cheapest, non-acidic and greener catalyst for Biginelli-type 3,4-dihydropyrimidin-2(1H)-ones (-thiones) synthesis. Mol Divers 2008; 13:5-25. [DOI: 10.1007/s11030-008-9094-8] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Accepted: 09/29/2008] [Indexed: 11/25/2022]
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